These actuating devices, which are also referred to as “actuating or switching magnets” are described, for example, in DE 101 04 998 A1 and are readily available on the market in a plurality of embodiments. The actuating part of the actuating magnet is essentially formed from a tubular pin which traverses a definable path when the coil winding is electrically excited by a connector socket which can be connected to the attachment plug plate. In doing so the actuating part triggers a switching or actuating process, for example, in a valve which is connected externally to shut off and route fluid flows. When no current is supplied and the switching magnet is therefore de-energized, it is generally reset via a reset spring located in the actuating device itself and/or on the valve to be actuated for another actuating process when the coil of the magnet armature is energized.
DE 10 2004 028 871 A1 discloses a generic actuating device in which the shape of the outside periphery of the actuating part is chosen for the shape of the inside periphery of a guide channel in the pole core. At least one fluid-carrying connection from the exterior to the armature space is then established to ensure the fluid-carrying and/or pressure-carrying connection of the valve interior to the interior of the actuating device necessary for proper operation in the form of the armature space via the guide channel. The guide channel is already available to support the actuating part in the pole core with a capacity to move. Since the guide channel is part of standardizable pole cores, in this way the fundamental prerequisite for a modular structure of the known actuating device solution is satisfied.
The cross-sectional surface of the guide channel is delimited by arc-shaped and/or rectilinear wall segments. The cross-sectional surface of the rod-like actuating part, in contrast thereto, is delimited, with the formation of the respective fluid-carrying connection, by further rectilinear and/or arc-shaped wall segments. The further wall segments at least in part are guided on the wall segments of the guide channel when the actuating part is moved. Accordingly, in the known solution, a plurality of possibilities are enabled for implementing the respective fluid-carrying connection by the corresponding configuration of the respective wall segments of the actuating part and the guide channel, guidance of the actuating part along the wall segments of the guide channel in the pole core still being ensured. In the simplest case, the cross-sectional surface of the guide channel is chosen to be round and, and when referenced to its cross section, the actuating part is a rod-shaped polygon. As a result of the cross-sectional surface which remains free, fluid-carrying connections which are dimensioned to be correspondingly large between the valve interior and armature space remain. Flow losses due to turbulent flow are avoided in this way as a result of the rectilinearly running fluid connections. In spite of these advantages, the known solution, with respect to the guidance of the actuating part within the pole core, is relatively complex and therefore expensive to implement. The rod-like actuating part is also guided by the pole core in its back region facing the armature space so that in the front free section region hindrances in operation may occur, to which the polygonal configuration of the actuating part also contributes.